Easy opening sheet metal container



June 7, 1938. w, F, PUNTE EASY OPENING SHEET METAL conmwma 2 Sheets-Sheet 1 Filed Jan. 28, 1937 June 7, 1938. w. 1 PUNTE EASY OPENING SHEET METAL CONTAINER 2 Sheets-Sheet 2 Filed Jan. 28, 1937 Patented June 7, 1938 UNITED STATES EASY creme snna'r METAL comma- William F. Punte, Syracuse, N. Y., assignor to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application January 28, 1937, Serial No. 122,851

3 Claims.

The invention relates to new and useful improvements in an easy opening sheet metal container wherein the metal is ruptured for providing an opening into the container.

It is the usual practice to thin the metal by plied externally to the thinned section of the metal, and whereinthe thinned section is so related to the metal wall containing the same that the same pressure or a greater pressure applied internally against the thinned section of the metal will not rupture the same.

A further object of the invention is to providean easy opening container of the above type which is shaped so as to provide a shoulder which is so related to the thinned section that a lever opener may be engaged with said shoulder and pressed against the thinned section for the rupturing of the metal.

In the drawings- Figure l is a view showing in vertical sectiona container for beverages to which the invention has been applied;

Fig. 2 is an enlarged sectional view through one side of the nozzle portion of the container;

Fig. 3 is a view similar to Fig. 2, but showing in broken lines the position of the thinned portion at the angle where pressure has been applied to the bottom wall almost to the point of rupturing the metal, and in full lines the metal after it;

is ruptured;

Fig. 4 is a view showing the nozzle portion of the container and with an opening lever applied thereto preparatory to exerting a pressure on the bottom wall of the depression for rupturing the metal;

Fig. 5 is a view showing applicants improvement as applied to a container end wherein a section of the metal adjacent one side of the endis thinned for rupturing;

Fig. 6 is an enlarged sectional view of a portion of the container end as shown in Fig. 5, and showing the lever opener applied for rupturing the metal, and

Fig. '7 is a view showing a slightly further modifled iorm of the invention wherein the thinned portion is concentric to the center of the end and disposed adjacent the double seam. a

The invention has to do with a container which is made fromsheet metal. A sheet'm'etal blank is cut to proper shape and then is formed into a body for the container. The edge portionsof the blank are joined by the usual side seam. The body is flanged and a bottom end is secured thereto by double seaming. In the drawings, two forms of containers are shown, one of which is particularly adapted for beverages. In the container'for beverages, the blank forming the top end is shaped so as to provide a nozzle. The metal at the upper end of the nozzle is formed with a depression. This depression is surrounded with a side wall, the lower portion of which is substantially at right angles to the bottom wall of the depression. The metal is thinned at the angle between the side wall and the bottom wall of the depression. This is done by die pressure applied to the inner surface of the bottom wall adjacent the angle so as to draw the metal at the angle and thus provide a thinned section joining the vertical wall of the depression with the bottom wall. When the metal is thinned in this particular region and in the manner'stated, external pressure applied to the bottom wall adjacent the side wall will place the thinned section under tension andwill cause the same to be stretched and finally ruptured. However, internal pressure against the bottom wall will produce a compression strain upon the thinned section, wherein the lines of force are within the metal in the side wall andno rupturing takes place. In the form of the invention shown in. other figures of the drawings, the can top which is seamed to the can body is the ordinary flat top, and said top is shaped so as to provide a side wall surrounding a depressedportion, andthe metal is similarly thinned atthe angle betweenthis side wall and the bottom wall of the depression. 7' 1 Referring more in detail to the drawings, the improved easy opening container, as shown in 1 Figures 1 to 4, includes a body portion l formed from a sheet metal blank, the edge portions of which are joined by an ordinary seam indicated at 2. The bottomend 2a of the container is drawn from a metal blank and secured to the body portion in the usual way by double-seaming. The container body and the bottom end are preferably made from tin plate which is enameled and baked in the flat. After the body is formed and the end attached thereto, a second coating of Y. enamel may be applied so as to cover the solderso i I "bonded side seam. The enamel coating is only used to prevent the contents of the can from contacting with the metal, and if the metal has no injurious efiect upon the contents which is to be placed in the can, then it is not necessary to apply a second coating of enamel, or even enamel the sheets in the fiat. The invention is not directed to the particular way in which the inner surface of the container is treated, but rather to the construction of the container whereby it may be of few parts and easily opened. Instead of attaching the can top 3 to the body I by a double seam, the can top and body may all be drawn from a single piece of metal and the number of parts further reduced while still providing a container that may be easily opened.

As shown in Fig. 1, the top end 3 is secured to the body portion l by a double-seam 4. This top end has a depressed raised portion terminating in a nozzle 5. At the upper-end, the metal .is shaped so as to provide a curved lip 6 and a shoulder 1 which curves upwardly slightly at its inner edge. The purpose of this shoulder will be stated later. The can top is drawn from a single sheet metal blank and the outer end of the nozzle is closed by metal which forms an integral part of the can top. The outer end of the nozzle .is provided with a depression 8 forming a side wall 9 which extends substantially at right angles to the bottom wall I0 where it joins said bottom wall. This wall 9 curves outwardly into the lip 6.

After the metal is formed with this depression 8 and the side wall arranged at right angles to the bottom wall I 0, then. the metal is subjected to die drawing in' the region of the angle between said side wall and the bottom wall. This die drawing action thins the metal at the angle. The thinnest section of the metal after this die drawing action lies in a line at substantially fortyfive degrees to the vertical wall and the bottom wall and midway between the two. While it is preferred to thin the metal at the angle so that the inner surface lies in the line a-b,' it will be understood that the metal may be otherwise shaped at this angular portion between the side wall and the bottom wall of the depression, but it is essential that the thinning of the metal shall take place substantially in that portion of the metal which joins the side wall to the bottom wall. The method of thinning the metal is described and claimed in my co-pending application Serial No. 122,852. filed of even date herewith;

The container is opened by pressure applied externally to the bottom wall of the depression. This may be done by any suitable tool, but a lever opener such as indicated at l I is preferred. The lever opener has a depending arm I2 which is shaped so as to extend beneath the shoulder 1. The inner face of this arm is curved to conform to the curvature of the shoulder, and the shoulder is curved upwardly at its inner portion so that the lever opener will be firmly engaged with the can top during the opening of the same. The lever opener is shaped so as to provide a projecting arm l3 which is adapted to contact with the bottom wall of the depression at a point sub stantially opposite where the lever opener engages the shoulder 1. The lever opener has a handle end I4 and when this handle end is raised, then the lever opener fulcruming on the shoulder will apply pressure against the bottom wall of the depression very close to the thinned portion. Fig. 3 shows in broken lines the condition of the metal parts after pressure has been applied through this lever opener almost to the point of rupturing the metal. It will be noted that .the bottom wall has been depressed and the thinned portion moved downward until it is almost in line with the side wall. In full lines in Fig. 3, the metal is shown as ruptured through a continued pressure of the lever opener against the bottom wall. The section 9a of the thinned por tion remainingintact with the side wall is positioned in alinement with the side wall 9 so that the raw edge of metal incident to the rupturing of the same faces substantially downward. After the metal has been ruptured-at the starting point, a further movement of the lever opener will cause the metal to rupture along a line determined by the thinned portion at the angle. The lower edge 15 of the lever opener terminates at a point l6 which is a short distance away from the vertical wall 9, and as a result, the metal will be ruptured along the thinned line throughout the by greater extent thereof, but a sufiicient portion will be retained intact to form a hinge and support the section which is torn away. This is of advantage in connection particularly with a container for a beverage, as it retains the ruptured metal within the container when the container is'inverted for pouring the contents through the opening formed.

While the metal can be readily ruptured through the aid of a suitable tool, when pressure is applied externally to the bottom wall, it will not be ruptured by a similar pressure or a greater pressure applied internally against the bottom wall. If the container is used for the packaging of beer, it is necessary to process the beer after the container is sealed, and during this treatment of the beer, an internal pressure develops which is substantially ninety pounds per square inch. There is also a considerable internal pressure on all carbonated beverages, and on all highly,

volatile products. When the internal pressure against the bottom wall of the depression exceeds the external pressure thereagainst, there are forces of compression exerted on the thinned section, which forces lie within and restrained by the metal in the side wall, and therefore, the metal will not be ruptured. Applicant has, therefore, provided an easy opening container wherein the metal is thinned, but thinned in such relation to the wall which contains the thinned portion that external pressure can be used for easily rupturing the metal, while internal pressure will not rupture the metal.

When the thinned portion is located at the .angle between the side wall of the depression and the bottom wall thereof, a relatively wide opening will be produced through which the contents may be poured. Furthermore, the metal is ruptured at a point well away from the lip 6, and the torn edge faces inwardly so' that there is no danger of the operator contacting with this raw edge, and the container is one wherein the nozzle can be placed in the mouth for drinking the contents.

In Figures 5 and 6 of the drawings, the invention is shown as applied to what is often referred to as an open top container. The container consists of the usual body portion I! to which a closure end I8 is secured by a double-seam 19. This closure end is die-shaped from a single piece of metal and is provided with a depression 20 surdouble seam joining the can top to thebqdy wall;

The arm 25 of the lever opener is adapted tobe' on the bottom wall of the depression adjacent side wall and will rupture the-metal, in it I ner above described. The doubleseam nasshoulder adjacent the thinned section ,orfmaar with which the lever openercooperates. This de-J pressed section maybe made relatively small when acontainer is intended for packaging liquids, and again it may be relatively large so that a'spoon may be inserted therethrough for the removing of the contents of the container.

In Fig. 7 there is a further modified for'm of construction for the 1 open top container. The

body portion IT has an end 28 secured thereto v by a double seam' 21. This container end is shaped so'as to provide an annular'upwardly and inwardly extending-portion 28 integrally joined to a central raised portion. The raised portion is depressed so as to form a recess 29 surrounded by a side wall 30. The bottom wall 3| of this depression is substantially at right angles to the lower portion of the side wall 30, and, the metal at the angle is drawn and thinned in the same manner as described in connection with- Figures 1 to 6. In this form of the invention, a lever' opener 32 is used in the manner illustrated in Fig. 7," The lever opener has an arm 33 which engages beneaththe shoulder at the double seam, and a portion 35 which is shaped so as to bear against the bottom wall of the depression at the point nearest where the arm 33 contacts with the double seam. The swinging of the lever opener will cause the metal to be ruptured and then the lever opener is moved along the double seam to another set position and again pressed against the bottom of the depression and by shifting the lever opener all the way around the can top, the bottom wall of the depression may in part, or in whole, be separated fromthe can top for the opening of the container. I

It will be noted that in each instance illustrated, the thinning of the metal takes place at the angle joining the lower portion of the side wall surrounding the depression with the bottom wall of the depression, and therefore, when pressure is applied against the bottom wall, tension forces will be created within the thinned portion and said thinned portion willbe pulled substantially into alinement with the side wall and finally ruptured. However, any internal pressure against the bottom wall of the depression will create compression forces within the thinned portion which lie within the metal and are restrained by the side wall so that no rupturing of the metal occurs.

It is apparent opening container has been provided wherein the metal may be readily ruptured by external pres-' sure, but internal pressure will not rupture the metal. various forms of products and beverages, such as carbonated beverages and beverages which are pasteurized after being sealed in a container. Then again, the weakening line may be reduced to a minimum for easy opening with the assurance that any pressure from within will not rupture the metal.

In the usual form of scoring metal, a die is used which cuts into the metal and this severs 'uctjwherein contact of the product with the tionfl'theclosure member may be separate and" attached to the can top. It iseSsential, howa ever, that the closure member shall havea desure will not rupture the same. It is also obvious pended claims.

. at right angles to the plane of the bottom wall The container, can therefore, be used for v on its inner surface if it is to for a proda deleterionseifect thereon;

f is preferred to-. form thei'c'antop with member. whichmayjbe ruptured alloneiintegral piece of-meta'l'. it, will be un erstood that from certain. aspects. of the inven l pression formed therein providing a side wall, the lower portion of which is substantially at right angles to the bottom wall, and that the metal shall be thinned at the angle between the side wall and the bottom wall so that it can be ruptured by external pressure, while internal presthat the invention may be applied to various forms of containers and may be modified as to details of construction without departing from the spirit of the invention as set forth in the ap- Having thus described the invention, what I claim as new and desire to secure by Letters Patcut, isv 1. An easy opening sheet metal pressure container comprising a body, top and bottom ends hermetically joined thereto, said top having a depression formed therein surrounded by a side I wall, the lower portion of which is substantially of the depression, the metal at the angle between the side wall and the bottom wall being shaped so as to provide a thinned portion with the maximum extent of thinness lying midway between the side wall and the bottom wall whereby external pressure applied to the bottom wall at a point adjacent the side wall will create within said thinned portion, tension forces which will rupture the same, and internal pressure applied to the bottom wall will create compression forces within said thinned portion which will be restrained by the vertical wall and the rupturing of the metal prevented. 2. A sheet metal pressure container comprising a body,. top and bottom ends hermetically joined thereto,.said top end being provided with a raised nozzle having the end thereof closed, said top end, nozzle and closure therefor being of one integral piece of metal, the closed end of said nozzle being provided with a central depression surrounded by a side wall, the lower portion of which is substantially at right angles to the bottom .wall of the depression, the metal at the angle between the side wall and the bottom wall being shaped so as to provide a thinned portion with the maximum extent of thinness lying midway between the side wall and the bottom wall I whereby external pressure applied to the bottom from the above that an easywall at a point adjacentthe side wall will create within said thinned portion, tension forces which will rupture the same, and internal pressure applied to thebottom wall will create compression ing a body, top and bottom ends hermetically joined thereto, said top end being provided with a raised nozzle having the end thereof closed, said top end, nozzle and closure therefor being of one integral piece of metal, the closed end of said nozzle being provided with a central depression surrounded by a side wall, the lower portion of which is substantially at right angles to the bottom'wall of the depression, the metal at the angle between the side wall and the bottom wall being thinned and disposed so that external pressure applied to the bottom wall at a point adjacent the side to form a smooth pouring lip, and a shoulder overhanging the outer wall oi the nozzle, which shoulder is curved upwardly on its under face so as to permit the engagement of a lever opener therewith for applying pressure to the bottom wall 01' the depression for the rupturing oi the metal.

WILLIAM F. PUNTE. 

